Conventionally, a semiconductor light emitting device has been known which is improved in the efficiency of light extraction from the semiconductor light emitting device by forming on a substrate multiple protruding portions made of a dielectric material having a refractive index different from that of the substrate, growing a nitride-based semiconductor layer on the substrate around the protruding portions, and then laterally growing the nitride-based semiconductor layer (Japanese Patent Application Publication No. 2008-153634).
In the semiconductor light emitting device, the protruding portions made of a ferroelectric material are divided into two groups, and different external electric fields are applied to the two groups, respectively. This makes the refractive indices of the respective two groups different from each other. Thereby, the light extraction efficiency of the semiconductor light emitting device is controlled.
In the semiconductor light emitting device, however, the difference in refractive index caused by the external electric fields is determined by the electro-optical properties of the ferroelectric material, and is in the order of several percent of the refractive index of the ferroelectric material at the most. As a result, a sufficient difference in the refractive index cannot be obtained, which causes a problem that a sufficient light extraction efficiency cannot be obtained.